Background: Many studies show a potentially harmful effect of right
ventricular pacemaker stimulation on left ventricular function. This is
unavoidable with conventional dual-chamber pacemakers. A subgroup of patients
with right ventricular stimulation develops a pacing-induced cardiomyopathy
(PiCMP). Biventricular pacemakers are a potential alternative. Objectives: As
long-term data on the prevalence of PiCMP are sparse, the aim of this study
was to determine the prevalence after right ventricular long-term stimulation
of at least 15 years. In addition, the effects on exercise capacity and
quality of life as well as dyssynchrony induced by right ventricular pacing
were evaluated. Methods: Inclusion criteria were right ventricular stimulation
for at least 15 years due to 3rd degree atrioventricular block and the absence
of structural heart disease at the time of initial implantation of the
pacemaker. PiCMP was de fined as LVEF 45%, dyskinesia in right ventricular
stimulation and the absence of other causes of cardiomyopathy. All patients
underwent echocardiography and spiroergometry, additionally the quality of
life was studied. Results: From a base of 1300 patients 26 met the inclusion
criteria. Echocardiography showed a statistically significant left ventricular
remodeling in PiCMP patients (LVEF 41.0 ± 4.5%, 54.0 ± LVEDD 2.7 mm) compared
to patients with preserved LVEF (LVEF 61,2 ± 5,8%, p = 0,0009, LVEDD 45,6 ±
4,0 mm, p = 0,004). There were no statistically significant differences in
terms of age, sex, BMI, duration of right ventricular stimulation, frequency
of sinus rhythm or the occurrence of arterial hypertension. The
interventricular mechanical delay was also not statistically significantly
different, but the longest intraventricular delay in patients with preserved
LVEF ( 65.5 ± 43.0 ms ) was statistically signi ficantly shorter compared to
patients with PiCMP ( 112.5 ± 15.0 ms, p = 0.042 ). Exercise capacity and
quality of life did not differ. Conclusions: Despite long-term right
ventricular stimulation (24.6 ± 6.6 years) there was only every 6th Patient
affected by PiCMP. The results suggest a slow increase of affected patients
after the first year. Furthermore, it was found that intraventricular - but
not interventricular - dyssynchrony contributes to the pathogenesis of PiCMP.
In general, implantation of the more expensive CRT devices in all patients
with higher grade atrioventricular block without structural heart disease to
avoid PiCMP is not justied. A routine echocardiographic assessment of LVEF one
year after pacemaker implantation for identifying patients for an upgrade is
recommended.